Authorities are blaming pilot error for a plane crash in Russia's northern republic of Karelia that killed 44 people after slamming into the ground and catching fire.

Deputy Prime Minister Sergei Ivanov, who oversees Russia's aviation industry, said Tuesday that it appears the pilot made a mistake while trying to land in heavy fog.

The plane, a Tupolev 134, was carrying 52 people, including nine crew members, veered off course while landing, clipped trees and hit a power line before crashing and burning just short of a runway at Petrozavodsk airport, about 650 kilometers northwest of Moscow.

Local Russians rescued eight people, including a nine-year-old boy and his 14-year-old sister, dragging them from the burning wreckage before it exploded. The eight survivors were taken to hospitals and are in critical condition.

Officials have recovered the aircraft's flight data recorders from the crash site. The plane was enroute from Moscow's Domodedovo airport to Petrozavodsk.

The passengers included two Ukrainians, a Swede, a Dutch national and four people with dual U.S. and Russian citizenship. Germany's Foreign Ministry says one victim had German-Russian dual citizenship.

It is the deadliest crash in Russia since Polish President Lech Kaczynski's plane went down near the western city of Smolensk in April 2010, killing all 96 people on board.